"Martie is doing very well and Gareth and the family are over the moon," her rep tells OK!.

She is the third child for Martie and her husband Gareth. Twin sisters Kathleen and Eva are 4. Open about her fertility issues, the 38-year-old singer conceived both pregnancies via in vitro fertilization.

Harper’s birth makes it a total of eight Dixie Chicks offspring in the last few years. Natalie Maines and Heroes star Adrian Pasdar have two sons, Jackson, 7, and Beckett, 4. Emily Robison and husband Charlie are parents to Gus, 5, and twins, Julianna and Benjamin, 3.